The main areas affected are in Germany (particularly the western Ruhr region) and the Netherlands, although other parts of Europe are also affected, with Belgium authorities recently having to destroy nests of the invasive species, as the BBC has reported. While the caterpillars are seen each year, a mild winter and an especially warm spring have seen numbers rise (a sign of global warming).
The typical period of concern is during May and June; over the next few weeks the caterpillars turn into pupae, then moths in late July. In terms of the risks to people, for the outbreak last year Digital Journal’s Karen Graham explains that the caterpillars “can cause vomiting, asthma attacks, and skin rashes. People are being warned to not touch or approach nests or caterpillars, or let children touch or approach nests or caterpillars.”
The oak processionary (Thaumetopoea processionea) is a moth whose caterpillars can be found in oak forests, and they are common to distributed in central and southern Europe. the caterpillars have a grey body and dark head, with very long, white hairs.
The caterpillars attack oak trees. The inch long (3 centimeters) caterpillars insects can be seen marching along in processions across treetops during night time, consume the young leaves on oak trees. The issue of public concern is due to the hairs that form on the body of the insect.
These hairs, as they detach, can be carried in wind currents and cause allergic reactions (skin irritation and asthma) in some people (the hairs are venomous setae, and the toxin is called thaumetopoein). And there can be a lot of hairs produced – a mature caterpillar can have up to 700,000 hairs. For this reason, a public health warning has been issued in several parts of Europe.
